The invention relates to a capacitor having at least one dielectric layer present between a flat electrode and an opposite flat electrode, in which the electrode(s) and the opposite electrode(s) are staggered with respect to each other in such a manner that in the plane of each time one of two oppositely located end faces of the capacitor they terminate and are contacted there by means of external connection contacts.
Capacitors, for example, ceramic multilayer capacitors, are produced in large numbers since, on the basis of their properties, they are particularly suitable for automatic printed circuit board mounting (SMD technology with surface mounted devices). Multilayer capacitors have a high volume capacity, i.e. they are not very bulky, they have the advantage of a large range of the capacity from pF to .mu.F and they can be manufactured in standardized dimensions.
In order to ensure the cost reduction and quality improvement which can be achieved by means of SMD techniques, high requirements are imposed upon all components used as regards rejection rate and units of the permissible capacity tolerances.
Ceramic multilayer capacitors are manufactured in known manner in that a foil is rolled or drawn from a suspension of a dielectric ceramic powder with a binder. The said foil is cut into individual plates, on which electrodes are provided by means of a metal paste in a silk screening method.
The printed green ceramic foils are stacked and packed under a high pressure. From the said sandwich pack individual capacitor bodies in the form of a sandwich stack are punched or cut before the binder is cured and the sandwich stack is sintered. According to this sintering process the contacting of the electrode layers is done by metallizing the opposing end faces of the capacitor body.
Associated with this method of manufacturing is that inhomogeneous starting materials or variable process parameters, such as time, temperature, composition of the sintering atmosphere or tolerances within the automatic production machines, for example, upon aligning tool and workpiece, lead to a deviation of the capacity from the desired value. By optimizing the manufacturing process, these error sources can be removed only partly not in the least because the price calculated on the market per component is limited and a large series manufacture may not be arbitrarily expensive.
Known multilayer capacitors are constructed as is shown in FIG. 3. Reference numeral 2 denotes the electrodes, 4 denotes the opposite electrodes, 6 are the outer connection contacts at the end faces of the capacitor and 8 denotes the dielectric layers. When the individual electrodes move with respect to each other in the x and in the y direction, as is shown in FIG. 4, the surface covered in common with the opposite electrodes following in the sandwich stack also vary so that according to the known laws of physics a capacity change occurs. This problem is not restricted to multilayer capacitors, but generally extends to flat capacitors having electric connections (external connection contacts) provided from oppositely located end faces, so, for example, plate capacitors.
According to the prior art the expert is capable of considerably compensating for shifts of the electrodes 2 in the y direction as shown in FIG. 4, in that each opposite electrode 4 is widened within the sandwich stack. FIG. 5 is a sectional view in the y direction through a sandwich stack having two electrodes 2 which are widened (FIG. 5a). The capacity of a multilayer capacitor constructed in such a manner varies only slightly so long as the opposite electrode 4, in spite of a movement about the length .DELTA.y, fully remains within the common overlapping area of its adjacent electrodes 2 (FIG. 5b). However, it is particularly desirable to also compensate for a lateral staggering of individual electrodes 2 in the x direction as is shown in FIG. 4, since the said lateral staggering in the x direction very essentially influences the values for the capacity.